1. Technical Field
The present invention relates to a cover structure of a machine tool for preventing cutting chips or cutting oil from scattering during machining of the machine tool, and specifically, to a cover structure of an automatic lathe for machining a rod-shaped workpiece. The invention also relates to a machine tool having such a cover structure.
2. Description of the Related Art
Generally, in an automatic lathe for sequentially producing a plurality of parts by machining an elongated material or a rod-shaped workpiece, or a shorter rod-shaped workpiece automatically supplied to the lathe, as shown in Japanese Unexamined Patent Publication No. 2001-310201, a movable separator chute for receiving a machined part and a box for containing the part moved on the separator chute, are provided. Accordingly, in a conventional automatic lathe for machining a rod-shaped workpiece, a cover for preventing cutting chips or cutting oil from scattering during machining normally covers not only a spindle and an adjacent area thereof, but also the entire automatic lathe for safety and structural reasons.
In an automatic lathe having a constitution as shown in Japanese Unexamined Patent Publication No. 2001-310201, a machined part separated from a spindle is contained in a box via a separator chute. Alternatively, in another known automatic lathe, a machined part separated from a spindle is positioned or dropped on a belt conveyor arranged within the lathe (or within the cover structure) instead of the box, and then the machined part is ejected from an outlet formed on a suitable place of the conveyor.
In the above automatic lathe, when either the box or the belt conveyor is used, the machined part cannot be immediately observed or checked. Further, it is difficult to separate the cutting oil or cutting tool from the machined part. In other words, in the case that machined parts are accumulated in the box, a door or the like arranged in the cover cannot be opened or closed during machining for safety reasons. Even if the box containing the machined part can be opened or closed, it may be troublesome to check the machined parts since cutting chips or cutting oil may scatter during machining. Therefore, in order to check a machined part, it is necessary to take out and check the part when the machining is complete or when the machining is purposely interrupted. Thus, it is difficult to check the part in an early stage of machining, resulting in a loss of efficiency if errors or problems occur during machining.
Also, if a belt conveyor is used, the machined part can be sequentially conveyed and ejected by the conveyor. Therefore, the machined part can be checked before a series of machining is complete, unlike the case of parts box. However, the belt conveyor is often intermittently operated in order to prevent the machined parts from becoming damaged by contacting each other, and further, the belt conveyor is arranged within the cover structure of the machine tool. Therefore, it takes considerable time to eject the machined part outside the machine tool by means of the belt conveyor via a separator chute, which means that an error or trouble in machining cannot be immediately found.